// Main purpose is to call ngram_core program define ngram *! 1.0.0 April 2017 version 13 syntax varlist (min=1 max=1) [if] [in], [ * ] // obs excluded by [if] [in] marksample touse , novarlist qui count if `touse' if r(N) == 0 { error 2000 } ngram_core `varlist' if `touse', `options' end